Program control



March 8, 1966 E. P. BULLARD Ill PROGRAM CONTROL 4 Sheets-Sheet 2 FiledMarch 25, 1964 INVENTOR.

EDWARD P. BULLARD III AT RNEY.

March 8, 1966 E. P. BULLARD PROGRAM CDNTROL 4 Sheets-Sheet 5 Filed March25, 1964 INVENTOR L'DWARD P. BULLARD '.l1I

ATTORNEY.

March 1966 E. P. BULLARD Ill PROGRAM CONTROL 4 Sheets-Sheet 4 FiledMarch 25. 1964 INVENTOR.

AT TOR NE Y.

ED ARD P. BULLARDIE United States Patent 3,238,621 PROGRAM CONTROLEdward P. Bullard III, Fairfield, Conn., assignor to The BullardCompany, Bridgeport, Conn., a corporation of Connecticut Filed Mar. 25,1964, Ser. No. 354,631 20 Claims. (Cl. 33-18) This invention relates tomachine tools, and particularly to an improved program control forcausing one or more tools to be moved through a cycle of operations inperforming work.

There are prior art devices in which a member is moved alongintersecting axes by a separate cam for each axis, which cams arerotated as a unit to cause the member to be moved through a cycle ofoperations. These devices, however, employ a rigid linkage between themovable member and the cam follower so that the power required to movethe movable member and the accuracy of its movement are both developedby the cam itself. Furthermore, the maximum angle or slope of thecontour on the cam edge cannot exceed 45 without the forces becomingexcessive. This, therefore, requires an excessively large diameter camfor any reasonable cycle of operations, and if it is kept small by usingmultiplying linkage between it and the movable member, the resultingerror is correspondingly increased.

In such prior known devices, peripheral, open-edge cams are employed.This requires a force always acting to maintain the follower on the camperiphery, which force must be in excess of required material cuttingforces so that cutting can occur with the member moving in onedirection, i.e., with the cam follower moving toward the axis ofrotation of the cam. This, therefore, requires the cam to effect atleast twice as much force to produce a cut with the member moving in theopposite direction.

Various template arrangements have heretofore been provided for causingtools to follow predetermined paths of travel in machining work. Thus,contouring in the machine tool field often involved a stylus following atemplate having a desired contour to control the movement of a toolholder to machine a workpiece to the desired shape. The design ofavailable tracer heads, for two-dimensional contouring, for example,comprises two inductive bridges which are positioned mechanically 90degrees relative to each other. When the stylus is undeflected (in anull position), both bridges are balanced and there is no output fromthe tracer head. Upon defiecting the stylus from its null position, eachbridge produces an AC. signal which is proportional to the magnitude ofthe deflection along the corresponding mechanical axis. As thedeflection passes through zero and is reversed, the phase of the signalreverses. Thus, the output of each bridge is an indication of thedirection and magnitude of the component of deflection along thecorresponding mechanical axis.

There is, however, a circular area about the null position of the stylusthat is a dead band, and deflections of the stylus must exceed theradius of this area to render the control eflective. This area providesan inherent source of error that reflects in the work being producedsinse the deflection of the stylus by the template will vary inaccordance with many factors including friction, surface speed andtemplate shape.

Known program controls of the above described type have limitedcapabilities in that they cannot produce sharp corner contours,re-entrant angle contours as well as many other contours that aredemanded in industry.

The principal object of this invention is to provide a program controlfor a movable tool support of a machine tool which will have thecapability of producing any desired contour on work, regardless ofshape.

Another object of the invention is to provide such a control thateliminates the inherent inaccuracies present in prior known tracercontrol devices.

Still another object of the invention is to provide such a control inwhich the pressure between a servo-follower and a template surface isindependent of the forces required to produce the desired machining, andis of a substantially low value.

A still further object of the invention is to provide such a control inwhich separate servo means act on separate templates for controlling themovement of the tool slide along separate axes, and in which successivepoints along the contours of the separate templates effect, throughservo and feedback means, the instantaneous displacements of the toolslide along the corresponding axes.

Another object of the invention is to provide such a control in whichthe templates are locked together and rotated through 360 relative tothe servo means to produce a complete cycle of operations. In this way,each succeeding point about the peripheral edges of the locked templatescombines the coordinates of each axis corresponding to that point,providing a resultant displacement of the tool slide in accordance withthe contour to be produced.

Although the principles of the invention are equally applicable to anynumber axis system, it will, for clarity, be described in relation to atwo-axis system; 7

In one aspect .of the invention, a work holder may be provided forsupporting work desired to be machined in accordance with a desiredcontour. The worksupport may be rotatable or non-rotatable. A member,stationary relative to the work support, may be located in position suchthat it can slidingly support a saddle for movement along an axisrelative to the work support.

In another aspect of the invention, a tool slide may be mounted on thesaddle for linear movement at right angles to the axis of movement ofthe saddle, and a tool or tools may be mounted on the tool slide foroperating on work held by the work support. Accordingly, the tool slideis capable of universal movement within a plane. If the work support isnon-rotatable, then the tools may be rotatable and vice versa.

In another aspect of the invention, fluid-operated means may be locatedbetween the stationary member and the saddle for reciprocating thelatter along its axis of motion. Separate fluid-operated means may beprovided between the saddle and tool slide for reciprocating the slidealong its axis of movement which is at right angles to the'axis ofmovement of the saddle. Pressure fluid is adapted to be suppliedselectively to the fluid-operated means for moving the saddle and slidealong their respective axes.

In another aspect of the invention, separate servo means may be employedto control the selective flow of pressure fluid to each of thefluid-operated means, and each servo means may be operated by a separaterotatable template means.

In still another aspect of the invention, the coordinates of thetemplate means for each axis of movement of the universally movableslide are proportional to the corresponding axis coordinates of thedesired path of movement of the slide for the contour desired to beproduced.

In a still further aspect of the invention, the separate template meansare rigidly fixed relative to each other and are rotated through apredetermined angle, usually 360, in producing the cycle of operationsof the tool slide.

In still another aspect of the invention, the servo means may comprise atransducer having means that is always displaced axially by the templatemeans and which involves no lost motion.

In a still further aspect of the invention, there is provided compositetemplate means for each axis of movement of the tool slide in whichseparate components of each composite template means controls the motionof the tool slide in one direction along the corresponding axis.

The above, other objects and novel features of the invention will becomeapparent from the following specification and accompanying drawingswhich are merely exemplary.

In the, drawings:

FIG. 1 is a front elevational view of certain parts of a machine tool towhich the principles of the invention have been applied;

FIG. 2 is a view similar to FIG. 1, showing additional parts of themachine tool to which the principles of the invention have been applied;

FIG. 3 is a view partly in section of the valve body of FIG. 2;

FIGS. 4-7, inclusive, disclose a modified form of tem' plate means;

FIG. 8 is a modified form of the invention in which rotary hydraulicmeans is employed to move the saddle and slide;

FIG. 9 is still another modified form of the invention in which twofour-way valve means are employed instead of one as disclosed in FIG. 1;

FIG. 10 is a view similar to FIG. 9, except that a rotary hydraulicmotor is employed for a linear hydraulic motor; and

FIG. 11 is .a section taken substantially along line 1111 of FIG. 9.

Referring to the drawings, and particularly to FIGS. 1 to 3, theprinciples of the invention are shown as applied to a machine toolincluding a rotatable work-supporting table 10 (FIG. I) mounted within abase 11 for rotation by a conventional headstock transmission (notshown). The table 10 may support a work holding fixture 12 within whicha workpiece 13 is rigidly mounted and upon which turning and facingoperations are to be performed, all in a predetermined cycle ofoperations.

The base 11 may include a portion 14 extending upwardly behind table 10(FIG. 2) and it may support a saddle 15 mounted for vertical slidingmovement along ways 16 on the machine base portion 14. A tool slide 17may be mounted for horizontal sliding movement along ways 18 on saddle15.

Referring to FIG. 2., a cylinder 19, fixed to the portion 14, may have apiston 20 therein, the. piston rod 21 of which is connected to saddle15. Fluid transmission lines 22 and 23 may connect opposite ends ofcylinder 19 to a valve body 24 that is mounted on a horizontallyreciprocable bracket 25 having a rack 26 thereon that meshes with a gear27 fixed to one end of a shaft 28. Another gear 29 fixed to shaft 28meshes with a vertical rack 30 that is fixed to the saddle 15.

Referring to FIG. 3, the valve body 24 includes an axially movable spool31 having disks 32 and 33 spaced therealong on each side of an inletport 34. A port 35 in valve body 24 leads to line 23, and a port 36leads to line 22. Exhaust lines 37 and 38 lead from body 24. A spring 39normally urges spool 31 upwardly against a lever 40 forming part of adouble roll stylus 41 that engages the peripheral surfaces of a templateassembly 42, all as will be more fully described later.

The design of the valve body 24 and spool 31 is such that very sharp andaccurately located edges are provided on the disks 32, .33, and theports 35 through 38 are precisely related so that any axial movement ofspool 31 on either side of a central or null position will introducepressure fluid into one end of cylinder 19 while exhausting the otherend.

The double roll stylus .41 may include a triangularly shaped plate 43pivoted at one of its apices 44 on valve body 24. The other two apices45 and 46 support rollers 47 and 48. Lever 40 is in g l with plate 43and i arranged such that it is at exactly right angles to thelongitudinal axis of spool 31 when the spool is in its null position.

From the foregoing it is evident that spool 31 is urged upwardly byspring 39 and tends to move plate 43 counterclockwise about pivot point44 until rollers 47 and/ or 48 contact the peripheral edge of templatemeans 42. At the beginning of a cycle of operations, the peripheral edgeof template means 42 will be such as to maintain lever 40 and spool 31in their null positions. As template means 42 is rotatedcounterclockwise, any point on its peripheral edge that tends to moveaway from roller 48 will permit spool 31 to raise, admitting pressurefluid to .line 23, forcing piston 20 and saddle 15 with it verticallydownward. Accordingly, rack 30 moves downwardly, effecting horizontalmovement of bracket 25 leftwardly while maintaining roller 48 in contactwith template means 42 and forcing lever 40 and spool 31 into their nullpositions. Thus, rack 30, pinions 27, 29 and horizontally sli-dable rack26 provide a feedback means which with valve body 24 and template means42 provides a servo control over the vertical movement of saddle 15.Regardless of the forces resisting the movement of saddle 15, the forcesbetween the template means 42 and valve spool 31 will always beindependent thereof and of substantially zero value.

Conversely, action of template means 42 on roller 47 moving it clockwiseabout pivot 44 will depress spool 31 against the action of spring 39.Movement of spool 31 downwardly admits pressure fluid into line 22 whileex hausting line 23, thereby forcing piston 20 and saddle 15 upwardly.The upward movement of saddle 15 moves' valve body 24 rightwardlythrough the action of the feedbock 30, 29, 27 and 26 until the nullposition of spool 31 is achieved,

A bracket 49 may be attached to saddle 15 for vertical movementtherewith. It may support a cylinder 50 having a piston 51 therein, therod 52 of which is connected to tool slide 17. Lines 53 and 54 lead fromopposite ends of cylinder 50 to a valve body 55 identical with valvebody 24. Valve body 55 is mounted on a horizontally reciprocable bracket56 having a rack 57 that meshes with a pinion 58 splined to a shaft 59.Shaft 59 has 'a gear 60 fixed to it that meshes with a rack 61integrally attached to tool slide 17.

The valve body 55 includes a spool 55 identical with spool 31 of valvebody 24 and it is axially moved by a lever 62 forming part of plate 63that is pivoted at 64 on valve body 55. Plate 63 includes rollers 65 and66 mounted thereon in a manner similar to the mounting of rollers 47 and48 on plate 43. Another template means 67 is provided for actuatingplate 63 in the same way that template means 42 actuates plate 43.

Thus, at the beginning of a cycle of operations, the template means 67maintains the spool 55' of valve body 55 in its null position.counterclockwise movement of plate 63- permits spool 55 to moveupwardly, causing pressure fluid to flow into the righthand end ofcylinder 50 while exhausting the lefthand end, thus moving piston 51andtool slide 17 leftwardly. The feedback means 57, 58, 59, 60 and 61return spool 55' to its null position. Additionally, movement of plate63 clockwise causes pressure fiuid to flow into the lefthand end ofcylinder 50, moving piston 51 and tool slide 17 rightwardly; and

the feedback means above referred to returns spool 55' to its nullposition.

The template means 42 and 67 are fixed to a shaft 68 that is rotated ina counterclockwise direction and has a worm gear 69 fixed thereto thatmeshes with a Worm 701 that is shown as geared through pinion 71 to alarge gear 72. The shaft 68 may be journaled in bearings mounted. on theportion 14 of base 11. v

Referring again to FIG. 1, a workpiece 13 is shown held'in the fixture12. The workpiece is to have its in-. ternal surface turned along abevel from B to C; turned from C to D; another bevel produced from D toE;

turned from E to F; faced from F to G; another turning from K to L; afacing from L to M; a turning from M to N; beveled from N to O; andfinally turned from P to Q. These operations, in the present embodiment,are to be performed in a cycle by tools 73, 74' and 75, all mountedonthe tool slide 17. The horizontal spacing of tools 73, 74 and 75 onslide 17 is dictated by the dimensions of the workpiece 13 and theoperations to be performed by each tool. In the embodiment disclosed,tool 73 is employed to produce all surfaces between points A to G,inclusive; tool 75 is used to machine surfaces from K through and tool74 is used only to turn the surface P to Q.

Obviously, tool74 must be spaced horizontally from tool 73 so thatduring its cutting operation, tool 74 will clear and ride on therighthand side of fixture 12. Furthermore, tool 75 isspaced'horizontally from tool 74 so that when the former is machiningsurfaces M to N, tool 74 will be to the left of surface P to Q.

The position of the cutting points of tools 73, 74 and 75 verticallydownward from the bottom end of 'slide 17 is determined by the amountofoverhang'necessary to permit required vertical motion withoutinterference between the workpiece and tool slide and between theworkpiece and tool tips.

Initially, the locations of the cutting tips of tools 73,

74 and 75 are laid out from the dimensions of the workpiece and the bestpath of movement of the tool slide 17 to producethe various machiningoperations in a programmed cycle. Thus, in the example shown, the pathof travel of the tool slide 17 has been determined so that the cuttingpoint of tool 73 follows the path A-B-C-D-E- F-G-H-J-K-L-M-N-O-P-Q-R-A.

The template means 42 is then designed so that its polar coordinates areproportional to corresponding coordinates along the vertical axis ofmotion of slide 17 to effect the above-referred-to path of movement oftool 73. And, the template means 67 is designed so that its polarcoordinates are proportional to corresponding coordinates along thehorizontal axis of motion of tool slide 17 to effect said path ofmovement.

It is felt that the design and construction of the template means 42 and67 can best be understood by describing the cycle of operationsperformed on the workpiece 13. Having made the tool layout and a layoutof the path of travel of the tool slide 17 as previously explained, itbecomes relatively simple to calculate the time required for each motionalong said path at a desired rate of feed for the material beingmachined and at desired traverse rates. A total of these individualtimes represents the time for the complete cycle and provides the datafrom which the polar coordinates of the template means can becalculated. Since template means 42 and 67 are fixed relative to eachother and are rotated through 360 to complete a program, the distancebetween each point A, B, C, etc., about the path can be represented by acorresponding distance between corresponding points A, B, C, etc., aboutthe template means 42 and 67. Furthermore, the rate of movement betweensucceeding points A, B, C, etc., about template means 42 and 67 will bethe slope of the effective template surface between said points.Expressed otherwise, it is the rate of change of radial distance betweentwo succeeding points.

The geometry of the plates 43 and 63 and the construction of templatemeans 42 and 67 are of considerable importance in the present invention.The template means 42 and '67 are composite template means, i.e,template means 42 comprises two components that are located in spacedparallel planes. Thus, composite template means 42 includes a templatecomponent 76, the peripheral edge of which is aligned and cooperateswith the roller 48. It also includes another template component 77, theperipheral edge of which is aligned and cooperates with roller 47. Inthe embodiment disclosed, the component 76 is employed to controlvertically downward movements of 6. the saddle 15 and with it, slide 17,while component 77 is employed to control vertically upward movements ofsaddle 15 and with it, slide 17 as well as periods of dwell of saddle 15in its vertical movement, which latter are produced by simply employingarcuate peripheral portions of component 77 having the center of saidarcuate portions at the axis of shaft 68.

Referring again to FIG. 3, it is evident that with the compositetemplate means 42 rotating in a counterclockwise direction, downwardmovement of saddle 15 is controlled by a surface on template component76, the slope of which is shown as dot-and-dash line 78, cooperatingwith roller 48, and the velocity of movement of saddle 15' will dependupon the slope of line 78. It is to be noted that the slope of line 78may be any place within the first and third quadrants and any anglebetween a vertical and a horizontal line, the former providing nodownward movement of saddle 15 as template means 42 rotatescounterclockwise, and the latter theoretically providing infinite speed.However, any angle less than horizontal would provide a finite rapidrate of movement of saddle 15, and any angle between vertical andhorizontal would be effective without interfering with the properfunctioning'of the plate 43.

Upward movement of saddle 15 is controlled by a surface of templatecomponent 77, the slope of which is shown as dot-and-dash line 79,cooperating with roller 47. The velocity of upward movement of saddle 15will depend upon the slope of line 79, and it may be any place withinthe second and fourth quadrants and any angle between vertical such asline 80 which is an arcuate line having its center at the axis of shaft68 and which provides a period of dwell with no upward movement ofsaddle 15, or it may be horizontal which would again provide atheoretically infinite speed of saddle 15.

In a similar fashion, the template means 67 may comprise a component 81,the peripheral edge of which is aligned and cooperates with the roller65. It also includes another template component 82, the peripheral edgeof which is aligned and cooperates with roller 66.

The component 81 is employed to control horizontal rightward movement ofslide 17 as well as periods of dwell, while the component 82 is employedto control horizontal leftward movement of the slide 17. The rollers 65and 66 on plate '63 cooperate with the slope of the various portions ofthe template components 81 and 82 in the same manner that the rollers 47and 48 cooperatewith template components 76 and 77.

Referring to FIG. 2, with the parts in the condition shown, the point onthe periphery of template component 76 along the line A acts on roller48, holding spool 31 in its null position, while roller 47 isineffective. Template component 81 is acting on roller 65, holding spool55 in its null position, while roller 66 in ineffective; and the cuttingpoint of tool 73 is at point A (FIG, 1).

As the combined template means 42 and 67 rotate in a counterclockwisedirection to point B, the roller 65 follows along a circular surface oftemplate segment 81 having its center at the axis of rotation of shaft68. Consequently, tool slide 17 is prevented from horizontal motion.However, during this rotation of template means 42, roller 48 followsthe surface on template component 76 between points A and B which has arelatively rapid change of slope, providing a rapid traverse movement ofsaddle 15 vertically downwardly until the cutting point of tool 73 is atpoint B. In the embodiment disclosed, no cutting occurs until thecutting point of tool 73 reaches point B, at which point a slow feedingoperation from B to C (FIG. 1) is effected. In order to provide atransition from rapid traverse to a slow feed rate downwardly, a curved,deceleration surface 83 on template component 76 is provided at point B.This curved surface 83 acts to decelerate the traverse motion so that noabrupt disruptoa slow feed motion.

In moving template means 42, 67 from point B to point C, the rate ofchange of slope of template component 76 is slight and such as toproduce a vertically downward movement of saddle 15. Since the velocityof saddle 15 is determined by this slope, a relatively slow feed rate ofmovement of saddle 15 occurs. Also, the slope of the template surfacefrom B to C on template component 81 is likewise slight, and such thatit acts on roller 65 to move spool 55' downwardly, thereby producing arightward movement of tool slide 17. The simultaneous action of rollers48 and 65 in the moving of template means 42 and 67 from B to C causesslide 17 simultaneously to move rightwardly and downwardly, producing aresultant motion from B to C on the path of travel of tool 73.

Continued counterclockwise movement of template means 42, 67 betweenpoints C and D thereon presents a circular (effective) portion ontemplate component 81 which cooperates with roller 65 and retains thetool slide 17 from horizontal motion, while the portion C to -D ontemplate component 76 acts on roller 48 to effect a downward movement ofsaddle 15 until the cutting point of tool 73 reaches point D, whereuponcomponent 81 acts on roller 65 simultaneously with component 76 actingon roller 46 to produce the beveled surface between points -D and E ofthe path of movement of tool 73,

1 Template component 81 between its points E to F follows a circularpath with its center at the axis of shaft 68, thus preventing horizontalmovement of tool slide 17. The portion of component 76 between itspoints E-F is a curve of progressively diminishing radii, causing spool31 to move upwardly, thereby causing saddle 15 to move downwardly at afeed rate determined by the rate at which the radii diminish over theextent of the portion E to F of component 76.

Portion F to G on component 77 is circular with its center at the axisof shaft 68. The action of roller 47 on this circular portion preventssaddle 15 from moving vertically. The portion F to G on component 81 isalong a line that acts on roller 65, forcing spool 55' downwardly,thereby effecting rightward movement of tool slide 17 until tool 7 3 isat point G in its path of travel.

From G to H on component 81 the curveis circular with its center on theaxis of shaft 68, preventing horizontal movement of tool slide 17. Theportion G to H on component -77 is an angular line having a slope with arapid rate of change which cooperates with roller 47. In order toprevent instant increase in speed from feed between F and G to rapidtraverse between G and H, an acceleration curve 84 is located at thetransitional point between these two portions. The portion between G andH on component 77 forces spool 31 downwardly and hence causes saddle 15to move vertically upwardly at a traverse rate, while slide 17 isrestrained from horizontal movement until the point of tool 73 is atpoint H in its path of travel. When the cutting point of tool 73 is atpoint H, the cutting tips of tools 74 and 75 are above the top of theworkpiece 13.

p The portion H to J on template component 77 is circular with itsradius center on the axis of shaft 68, cooperating with roller 47 andpreventing vertical motion of saddle 15. The portion H to J on templatecomponent 82 provides a rapid rate of change and cooperates with roller66, permitting spool 55 to rise, hence elfecting horizontal traverse ofslide 17 leftwardly until the point of tool 73 is a point J. Since theportion G to H on component 81 was circular, and portion H to J oncomponent 82 is a rapid traverse slope, an accelerating curved portion85 is provided at the beginning of this traverse motion. This traversemotion positions tool 74 above the bore in the internal hub of workpiece13, and locates tool 75 in position to machine the outer periphery ofsaid hub.

The J to K portion of template component 81 is circular with its radiuscenter on the axis of shaft 68, thereby preventing horizontal movementof tool slide 17. Ac-

cordingly, a deceleration curve 86 is provided at the end of portion Hto J -on component 82. The portion J to K on template component 76 is arapidly changing sloped line. It cooperates with roller 48, causingspool 40 to rise, effecting vertically downward movement of saddle 15until the point of tool 73 is at point K in its path of travel. Thislocates the cutting tip of tool at point K for turning the CD. of theinternal hub of the workpiece 13, and locates tool 74 over the bore ofsaid hub With its cutting tip to the left of, and clearing the borewall.

The portion K to L on template component 81 is circular with a radius onthe axis of shaft 68, preventing horizontal movement of tool slide 17.The portion K to L on template component 76 is a relatively steeplyinclined surface cooperating with roller 48 to permit spool 31 to rise,effecting a relatively fast downward movement of saddle 15 until thecutting tip of tool 75 arrives at point L in its path of travel. This ispossible since the surface from K to L on workpiece 13 is a non-criticalsurface and can be machined rapidly.

The L to M portion of template component 77 is circular, having itscenter on the axis of shaft 68, preventing the vertical movement ofsaddle 15. The L to M portion of template component 81 is a rise actingon roller 65 to effect rightward movement of tool slide 17 until the tipof tool 75 is at point M.

The M to N portion of template component 81 is circular with a radius onthe axis of shaft 68 so that tool slide 17 is prevented from horizontalmovement. The portion M to N on template component 76 cooperates withroller 48, permitting spool 31 to rise and moving saddle 15 downwardlyuntil the tip of tool 75 reaches point N.

The portions N to O on template components 76 and 82 cooperate withrollers 48 and 66, respectively, to produce feed rates which combine togive the bevel N to O in the path of travel of tool 75. This places thecutting point of tool 74 at point 0 within the confines of the bore ofthe hub of workpiece 13. The portion 0 to P on template component 77 iscircular with a radius on the axis of shaft 68, preventing verticalmovement of saddle 15. The portion 0 to P on template component 81 has arapid rate of change of slope and operates roller 65 to effect rightwardmovement of tool slide 17 at traverse rate until. the tip of tool 74 isat point P within the hub bore. 7

The portion P to Q on template component 81 is circular with its centeron the axis of shaft 68, preventing horizontal movement of tool slide17. The portion P to Q on template component 77 has a slight rate ofchange of slope such that it cooperates with roller 47, forcing spool 31downwardly, causing saddle 15 to move upwardly at a feed rate until itreaches point Q in its path of travel.

The Q to R portion of template component 81 is circular having itscenter on the axis of shaft 68, thereby preventing horizontal movementof slide 17. The Q to R portion on template component 77 traversessaddle 15 upwardly to point R in the path of travel of tool 73.

The portion R to S of both template components 77 and 81 act on rollers47 and 65, simultaneously forcing spools 31 and 55' downwardly, therebyeffecting simultaneous movement of tool slide 17 rightwardly and saddle15 upwardly until the cutting tip of tool 73 is at point A and tools 74and '75 are in the position shown in FIG. 1.

The portion of template components 77 and 81 between S and A iscircular, preventing movement of tool slide 17 or saddle 15. At thispoint, the cycle is completed, the driving means for template means 42and 67 is deenergized, the finished workpiece 13 is replaced by anunmachined piece, and the cycle is repeated.

From the foregoing it is evident that critical dimensions on theworkpiece are held by the rollers on the styluses 63 and 41 acting oncircular paths on the template components. Since circular paths can beprecisely ground, no problem is presented in holding accurate sizes.Furthermore, the generation of curves of varying rates of slope betweensucceeding points on the template need not be precise, since slightvariations therein merely change the rate of feed or traverse slightly.Additionally, with the double roller stylus principle and the templatecomponents for each of the template means 67 and 42, overlapping ofsurfaces between the template components may be used to ensure positioncontrol of the styluses at all times.

As was previously described in connection with FIG. 3, the effectiveperipheral portion of the template means 42 acts on rollers 48 and 47,depending upon whether the effective portion is along a line lying inthe first and third quadrants, or in the second and fourth quadrants,respectively. Such an arrangement requires providing clearance on thenon-effective portion of the template means so that it will notinterfere with the non-effective roller 48 or 47 as the case may be.This requires the production of template components 76 and 77 ofsubstantially different contour and consequently they are moretime-consuming in preparing. The same applies to the components 81 and82.

It has been found that the clearance feature can be applied tonon-rotary styluses and in so doing, the template means may be composedof components of identical contour, one being of a different size thanthe other by an amount equal to the distance between the two styluses.

Referring to FIG. 4 to 7, inclusive, and particularly to FIGS. 6 and 7,the plate 43 is shown as provided with two non-rotatable styluses 90 and91 spaced apart the same distance that styluses 47 and 48 are spaced inFIG. 2. The effective portion of stylus 90 (FIG. 6) lies in the secondquadrant. And, stylus 91includes an effective portion 93 lying in thethird quadrant. The remainder of the styluses 90 and 91 is relieved toprovide clearance as will be explained.

Since both components 94 and 95 of the template means 96, correspondingto template means 42 (FIG. 2), have peripheral surfaces of identicalcontour, the lines 97 and 98 (FIG. 6) represent corresponding portionson 94 and 95 that lie in the first and third quadrants. It is apparentfrom FIG. 6 that the line 97 is in active position with stylus quadrant92, and that line 98 lies within the clearance portion of the stylus 91.This same condition will prevail for all lines 97, 98 between verticaland horizontal so long as they lie within the first and third quadrants.

In a similar fashion, lines 99 and 100 represent corresponding portionson components 94 and 95 that lie in the second and fourth quadrants. Itis apparent from FIG. 6 that line 99 is in active position with quadrant93 of stylus 91; and that line 100 lies within the clearance portion ofstylus 90. This same condition will prevail for all lines 99 and 100between vertical and horizontal so long as they are within the secondand fourth quadrants.

Referring to FIG. 5, the plate 63 corresponding to the plate 63 of FIG.2 is provided with styluses 90, 91 having an effective quadrant 101'similar to quadrant 92; and a stylus having an effective quadrant 102similar to quadrant 93 of FIG. 6.

From the foregoing it is evident that as the components 94, 95 and 101,102 rotate together in a counterclockwise direction, the cycle ofoperations produced by them will be identical to that produced bycomponents 76, 77; and 81, 82 of FIG. 2. Furthermore, since thecomponents 94, 95 have the exact same contour, but of a different size,their manufacture will be substantially easier than the manufacture ofdissimilar components such as 76, 77.

Referring to FIGS. 8 to 11, inclusive, certain modified forms of theinvention are shown. Thus, in FIG. 8, cylinder 19 and piston 20 havebeen replaced by a reversible hydraulic motor 103, the output shaft ofwhich has fixed to it a worm 104 that meshes with a worm gear 105. Thegear 105 is permitted to rotate but is restrained against axialmovement. Gear 105 is threaded onto a rod 106 that is fixed to saddle15. A similar arrangement may be provided for slide 17, FIG. 2 (notshown in FIG. 8).

In FIG. 9, an additional four-way valve 107 may be located between valve24 and cylinder 19. Referring to FIG. 11, the valve 107 is shown asincluding a stem 108 slidingly supporting pistons 109, 110 at each endthereof. Constant pressure from lines 111, 112 forces pistons 109, 110in opposite directions, maintaining spools 113, 114 in the positionshown in FIG. 11. Raising of lever 40 of valve 24 causes pressure fluidfrom line 34 to enter line 23, forcing piston 109 and stem 108leftwardly since the fluid also acts on the end of stem 108. Piston 110,however, remains in its rightward position. This admits pressure fluidfrom a line 115 to line 23, causing piston 20 to move downwardly, andwith it, saddle 15.

Movement of lever 40 downwardly admits pressure fluid to line 22,forcing piston 110 and stem 108 rightwardly, admitting pressure fluidfrom line 115 to line 22 which moves piston 20 upwardly and with it,saddle 15. There may be another auxiliary or supplementary valve 107Within the hydraulic circuit for the slide 17 between valve 55andcylinder 50 (FIG. 2). This arrangement makes it possible to use anyhigh pressure fluid from line 115 and still use a relatively lowpressure fluid in line 34 to thereby reduce to a minimum the force ofthe styluses against the template components.

In FIG. 10, the cylinder 19 and piston 20 of FIG. 9 have been replacedby the hydraulic rotary motor 103, while the supplementary four-wayvalve 107 is still retained.

Although the various features of the improved program control have beenshown and described in detail to fully disclose several embodiments ofthe invention, it will be evident that changes may be made in suchdetails and certain features may be used Without others withoutdeparting from the principles of the invention.

What is claimed is:

1. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; separate template means foreach axis of movement of said member, the coordinates of each templatemeans being proportional to the corresponding axis coordinates of thedesired path of movement of said member; separate servo means for eachtemplate means adapted to be operated by its corresponding templatemeans for controlling the corresponding power means for said member;feedback means responsive to the movement of said member along the axiscorresponding to said servo means for controlling said servo means; andmeans for moving all of said template means in unison relative to saidservo means, the construction and arrangement of the parts being suchthat the velocity of the movable member can be controlled as it is movedbetween any two successive points in its path of travel by the slope ofthe effective template surface between the corresponding templatecoordinates of said points.

2. Apparatus comprising in combination, a member; separate piston andcylinder means for moving said member along a plurality of intersectingaxes in accordance with a predetermined program; separate template meansfor each axis of movement of said member, the coordinates of eachtemplate means being proportional to the corresponding axis coordinatesof the desired path of movement of said member; separate servo means foreach template means adapted to be operated by its corresponding templatemeans for controlling the corresponding piston and cylinder means forsaid member; feedback means responsive to the movement of said memberalong the axis corresponding to said servo means for controlling saidservo means; and means for moving all of said template means in unisonrelative to said servo means, the construction and arrangement of theparts being such that the velocity of the movable member can becontrolled as it is moved between any two successive points in its pathof travel by the slope of the effective template surface between thecorresponding template coordinates of said points.

3. Apparatus comprising in combination, a member; separate rotary meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; separate template means foreach axis of movement of said member, the coordinates of each templatemeans being proportional to the corresponding axis coordinates of thedesired path of movement of said member; separate servo means for eachtemplate means adapted to be operated by its corresponding templatemeans for controlling the corresponding rotary means for said member;feedback means responsive to the movement of said member along the axiscorresponding to said servo means for controlling said servo means; andmeans for moving all of said template means in unison relative to saidservo means, the construction and arrangement of the parts being suchthat the velocity of the movable member can be controlled as it is movedbetween any two successive points in its path of travel by the slope ofthe effective template surface between the corresponding templatecoordinates of said points.

4. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; separate template means foreach axis of movement of said member, the coordinates of each templatemeans being proportional to the corresponding axis coordinates of thedesired path of movement of said member; separate servo means for eachtemplate means adapted to be operated by its corresponding templatemeans for controlling the corresponding power means for said member,said servo means including series arranged valve means between saidtemplate means and said power means, each including its own source ofpressure fluid; feedback means responsive to the movement of said memberalong the axis corresponding to said servo means for controlling saidservo means; and means for moving all of said template means in unisonrelative to said servo means, the construction and arrangement of theparts being such that the velocity of the movable member can becontrolled as it is moved between any two successive points in its pathof travel by the slope of the effective template surface between thecorresponding template coordinates of said points.

5. Apparatus comprising in combination, a member; separate rotary meansfor moving said member along a plurality of intersecting axes inaccordance with a pre determined program; separate template means foreach axis of movement of said member, the coordinates of each templatemeans being proportional to the corresponding axis coordinates of thedesired path of movement of said member; separate servo means for eachtemplate means adapted to be operated by its corresponding templatemeans for controlling the corresponding rotary means for said member,said servo means including series arranged four-way valve means betweensaid template means and said rotary means, each including its own sourceof pressure fluid; feedback means responsive to the movement of saidmember along the axis corresponding to said servo means for controllingsaid servo means; and means for moving all of said template means inunison relative to said servo means, the construction and arrangement ofthe parts being such that the velocity of the movable member can becontrolled as it is moved between any two successive points in its pathof travel by the slope of the effective template surface between thecorresponding template coordinates of said points.

6. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; separate rotatable templatemeans for each axis of movement of said member, the polar coordinates of.each rotatable template means being proportional to the correspondingaxis rectangular coordinate of the desired path of movement of saidmember; separate servo means for each template means adapted to beoperated by its corresponding template means for controlling thecorresponding power means for said member; feedback means responsive tothe movement of said member along the axis corresponding to said servomeans for controlling said servo means; and means for rotating all ofsaid template means in unison relative to said servo means, theconstruction and arrangement of the parts being such that the velocityof the movable member can be controlled as it is moved between any twosuccessive points in its path of travel by the slope of the effectivesurface of the template means between the corresponding polarcoordinates thereof.

7. Apparatus comprising in combination, a member; separate piston andcylinder means for moving said member along a plurality of intersectingaxes in accordance with a predetermined program; separate rotatabletemplate means for each axis of movement of said member, the polarcoordinates of each rotatable template means being proportional to thecorresponding axis rectangular coordinates of the desired path ofmovement of said member; separate servo means for each template meansadapted to be operated by its corresponding template means forcontrolling the corresponding piston and cylinder means for said member;feedback means responsive to the movement of said member along the axiscorresponding to said servo means for controlling said servo means; andmeans for rotating all of said template means in unison relative to saidservo means, the construction and arrangement of the parts being suchthat the velocity of the movable member can be controlled as it is movedbetween any two successive points in its path of travel by the slope ofthe effective surface of the template means between the correspondingpolar coordinates thereof.

8. Apparatus comprising in combination, a member; separate rotary meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; separate rotatable templatemeans for each axis of movement of said member, the polar coordinates ofeach rotatable template means being proportional to the correspondingaxis rectangular coordinates of the desired path of movement of saidmember; separate servo means for each template means adapted to beoperated by its cooresponding template means for controlling thecorresponding rotary means for said member; feedback means responsive tothe movement of said member along the axis corresponding to said servomeans for controlling said servo means; and means for rotating all ofsaid template means in unison relative to said servo means, theconstruction and arrangement of the parts being such that the velocityof the movable member can be controlled as it is moved between any twosuccessive points in its path of travel by the slope of the effectivesurface of the template means between the corresponding polarcoordinates thereof.

9. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; separate rotatable templatemeans for each axis of movement of said member, the polar coordinates ofeach rotatable template means being proportional to the correspondingaxis rectangular coordinates of the desired path of movement of saidmember; separate servo means for each template means adapted to beoperated by its corresponding template means for con- 13 trolling thecorresponding power means for said member, said servo means includingseries arranged valve means between said template means and said powermeans, each including its own source of pressure fluid; feedback meansresponsive to the movement of said member along the axis correspond-ingto said servo means for controlling said servo means; and means forrotating all of said template means in unison relative to said servomeans, the construction and arrangement of the parts being such that thevelocity of the movable member can be controlled as it is moved betweenany two successive points in its path of travel by the slope of theeffective surface of the template means between the correspondingpolarcoordinates thereof.

10. Apparatus comprising in combination, a member; separate rotary meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; separate rotatable templatemeans for each axis of movement of said member, the polar coordinates ofeach rotatable template means being proportional to the correspondingaxis rectangular coordinates of the desired path of movement of saidmember; separate servo said servo means; and means for rotating all ofsaid template means in unison relative to said servo means, theconstruction and arrangement of the parts being such that the velocityof the movable member can be controlled as it is moved between any twosuccessive points in its path of travel by the slope of the effectivesurface of the template means between the corresponding polarcoordinates thereof.

11. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; composite template means foreach axis of movement of said member, including separate components foreach direction of movement of said member along the corresponding axis,the coordinates of each composite template means being proportional tothe corresponding axis coordinates of the desired path of movement ofsaid member; separate stylus means for each component of each compositetemplate means; separate servo means for each of said composite templatemeans adapted to be operated by its corresponding composite templatemeans for controlling the corresponding power means for said member;feedback means responsive to the movement of said member along the axiscorresponding to said servo means for controlling said servo means; andmeans for moving all of said template means in unison relative to saidservo means, the construction and arrangement of the parts being suchthat the velocity of the movable member can be controlled as it is movedbetween any two successive points in its path of travel by the slope ofthe effective surface of the template means between the correspondingtemplate coordinates.

12. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; rotatable composite templatemeans for each axis of movement of said member, including separatecomponents for each direction of movement of said member along thecorresponding axis, the polar coordinates of each composite templatemeans being proportional to the corresponding axis coordinates of thedesired path of movement of said member; separate stylus means for eachcomponent of each composite template means; separate servo means foreach of said composite template means adapted to be operated by itscorresponding composite template means for controlling the correspondingpower means for said member; feedback means responsive to the movementof said member along the axis corresponding to said servo means forcontrolling said servo means; and means for moving all of said templatemeans in unison relative to said servo means, the construction andarrangement of the parts being such that the velocity of the movablemember can be controlled as it is moved between any two successivepoints in its path of travel by the slope of the effective surface ofthe template means between the corresponding template coordinates.

13. Apparatus comprisingin combination, a member; separate piston andcylinder means for moving said member along a plurality of intersectingaxes in accordance with a predetermined program; composite templatemeans for each axis of movement of said member, including separatecomponents for each direction of movement of said member along thecorresponding axis, the coordinates of each composite template meansbeing proportional to the corresponding axis coordinates of the desiredpath of movement of said member; separate stylus means for eachcomponent of each composite template means; separate servo means foreach of said composite template means adapted to be operated by itscorresponding composite template means for controlling the correspondingpiston and cylinder means for said member; feedback means responsive tothe movement of said member along the axis corresponding to said servomeans for controlling'said servo means; and means for moving all of saidtemplate means in unison relative to said servo means, the constructionand'arrangement of the parts being such that the velocity of the movablemember can be controlled as it is moved between any two successivepoints in its path of travel by the slope of the effective surface ofthe template means between the corresponding template coordinates.

14. Apparatus comprising in combination, a member; separate rotary meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; composite template means foreach axis of movement of said member, including separate components foreach direction of move-ment of said-member along the corresponding axis,the coordinates of each composite template means being proportional tothe corresponding axis coordinates of the desired path of movement ofsaid member; separate stylus means for each component of each compositetemplate means; separate servo means for each of said composite templatemeans adapted to be operated by its corresponding composite templatemeans for controlling the corresponding rotary means for said member;feedback means responsive to the movement of said member along the axiscorresponding to said servo means for controlling said servo means; andmeans for moving all of said template means in unison relative to saidservo means, the construction and arrangement of the parts being suchthat the velocity of the movable member can be controlled as it is movedbetween any two successive points in its path of travel by'the slope ofthe effective surface of the template means between the correspondingtemplate coordinates.

15. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; composite template means foreach axis of movement of said member, including separate components foreach direction of movement of said member along the corresponding axis,the coordinates of each composite template means being proportional .tothe corresponding axis coordinates of the desired path of movement ofsaid member; separate stylus means for each component of each compositetemplate means; separate servo means for each of said composite templatemeans adapted to be operated by its corresponding composite templatemeans for controlling the corresponding power means for said member,said servo means including series arranged four-way valve means betweensaid template means and said power means, each including its own sourceof pressure fluid; feedback means responsive to the movement of saidmember along the axis corresponding to said servo means for controllingsaid servo means; and means for moving all of said template means inunison relative to said servo means, .the construction and arrangementof the parts being such that the velocity of the movable member can becontrolled as it is moved between any two successive points in its pathof travel by .the slope of the effective surface of the template meansbetween the corresponding template coordinates.

16. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; composite template means foreach axis of movement of said member, including separate components foreach direction of movement of said member along the corresponding axis,the coordinates of each composite template means being proportional tothe corresponding axis coordinates of the desired path of movement ofsaid member, each component of a composite template means beingidentical in contour but of different radial dimensions; separate stylusmeans for each component of each composite template means, said stylusmeans including means, which when it is effective on one of saidcomponents the other stylus means is ineffective on said othercomponent; separate servo means for each of said composite templatesmeans adapted to be operated by its corresponding composite templatemeans for controlling the corresponding power means for said member;feedback means responsive to the movement of said member along the axiscorresponding to said servo means for controlling said servo means; andmeans for moving all of said template means in unison relative to saidservo means, the construction and arrangement of the parts being suchthat the velocity of the movable member can be controlled as it is movedbetween any two successive points in its path of travel by the slope ofthe effective surface of the template means between the correspondingtemplate coordinates.

17. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; composite template means foreach axis of movement of said member, including separate components foreach direction of movement of said member along the corresponding axis,the coordinates of each composite template means being proportional tothe corresponding axis coordinates of the desired path of movement ofsaid member; separate stylus means for each component of each compositetemplate means, the separate stylus means for each composite templatemeans includes a different template engaging portion for each componentthereof, whereby when a surface of one of the components of saidcomposite template means engages the effective portion of its stylus,the corresponding surface of the other component of said compositetemplate means does not engage the effective portion of its stylus;separate servo means for each of said composite template means adaptedto be operated by its corresponding composite template means forcontrolling the corresponding power means for said member; feedbackmeans responsive to the movement of said member along the axiscorresponding to said servo means for controlling said servo means; andmeans for moving all of said template means in unison relative to saidservo means, the construction and arrangement of the parts being suchthat the velocity of the movable member can be controlled as it is movedbetween any .two successive points in its path of travel by the slope ofthe effective surface of the template means between the correspondingtemplate coordinates.

18. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; composite template means foreach axis of movement of said member, including separate components foreach direction of movement of said member along the corresponding axis,the coordinates of each composite template means being proportional tothe corresponding axis coordinates of the desired path of movement ofsaid member; separate stylus means for each component of each of saidcomposite template means, said stylus means being mounted on, and spacedequally from a pivot point of a stylus carrier; an arm integral withsaid carrier and parallel to a line extending between said stylus means;separate servo means for each of said composite template means includingvalve means having a purely axially movable valve stem adapted to beoperated by said arm; feedback means responsive to the movement of saidmember along the axis corresponding to said servo means for controllingsaid servo means; and means for moving all of said template means inunison relative to said servo means, the construction and arrangement ofthe parts being such that the velocity of the movable member can becontrolled as it is moved between any two successive points in its pathof travel by the slope of the effective surface of the template meansbetween the corresponding template coordinates.

19. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; composite template means foreach axis of movement of said member, including separate components foreach direction of movement of said membr along the corresponding axis,the coordinates of each composite template means being proportional tothe corresponding axis coordinates of the desired path of movement ofsaid member; separate stylus means for each component of each compositetemplate means, the separate stylus means for components of one of thecomposite template means includes an effective portion covering thesecond quadrant, and the stylus means for the other component of saidone composite template means includes an effective portion covering thethird quadrant; separate servo means for each of said composite templatemeans adapted to be operated by its corresponding composite templatemeans for controlling the corresponding power means for said member;feedback means responsive to the movement of said member along the axiscorresponding to said servo means for controlling said servo means; andmeans for moving all of said template means in unison relative to saidservo means, the construction and arrangement of the parts being suchthat the velocity of the movable member can be controlled as it is movedbetween any two successive points in its path of travel by the slope ofthe effective surface of the template means between the correspondingtemplate coordinates.

20. Apparatus comprising in combination, a member; separate power meansfor moving said member along a plurality of intersecting axes inaccordance with a predetermined program; composite template means foreach axis of movement of .said member, including separate components foreach direction of movement of said member along the corresponding axis,the coordinates of each composite template means being proportional tothe corresponding axis coordinates of the desired path of movement ofsaid member; separate stylus means for each component of each of saidcomposite temp-late means, said stylus means being mounted on, andspaced equally from a pivot point of a stylus carrier, the separatestylus means for one of the components of the composite template meansincludes an effective portion covering the second quadrant, and thestylus means for the other component of said composite template meansincludes an effective portion covering the third quadrant; an armintegral with said carrier and parallel to a line extending between saidstylus means; separate servo means for each of said composite templatemeans including valve means having a purely axially movable valve stemadapted to be operated by said arm; feedback means responsive to themovement of said member along the aXis corresponding to said servo meansfor controlling said servo means; and means for moving all of saidtemplate means in unison relative to said servo means, the constructionand arrangement of the parts being such that the velocity of the movablemember can be controlled as it is moved between any two successivepoints in its path of travel by the slope of the effective surface ofthe template means between the corresponding template coordinates.

No references cited.

ISAAC LISANN, Primary Examiner.

1. APPARATUS COMPRISING IN COMBINATION, A MEMBER; SEPARATE POWER MEANSFOR MOVING SAID MEMBER ALONG A PLURALITY OF INTERSECTING AXES INACCORDANCE WITH A PREDETERMINED PROGRAM; SEPARATE TEMPLATE MEANS FOREACH AXIS OF MOVEMENT OF SAID MEMBER, THE COORDINATES OF EACH TEMPLATEMEANS BEING PROPORTIONAL TO THE CORRESPONDING AXIS COORDINATES OF THEDESIRED PATH OF MOVEMENT OF SAID MEMBER; SEPARATE SERVO MEANS FOR EACHTEMPLATE MEANS ADAPTED TO BE OPERATED BY ITS CORRESPONDING TEMPLATEMEANS FOR CONTROLLING THE CORRESPONDING POWER MEANS FOR SAID MEMBER;FEEDBACK MEANS RESPONSIVE TO THE MOVEMENT OF SAID MEMBER ALONG THE AXISCORRESPONDING TO SAID SERVO MEANS FOR CONTROLLING SAID SERVO MEANS; ANDMEANS FOR MOVING ALL OF SAID TEMPLATE MEANS IN UNISON RELATIVE TO SAIDSERVO MEANS, THE CONSTRUCTION AND ARRANGEMENT OF THE PARTS BEING SUCHTHAT THE VELOCITY OF THE MOVABLE MEMBER CAN BE CONTROLLED AS IT IS MOVEDBETWEEN ANY TWO SUCCESSIVE POINTS IN ITS PATH OF TRAVEL BY THE SLOPE OFTHE EFFECTIVE TEMPLATE SURFACE BETWEEN THE CORRESPONDING TEMPLATECOORDINATES OF SAID POINTS.